<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="./css/index.css" />
    <title>记事本</title>
</head>

<body>

    <!-- 主体区域 -->
    <section id="app">
        <!-- 输入框 -->
        <header class="header">
            <h1>小黑记事本</h1>
            <input placeholder="请输入任务" class="new-todo" v-model="todoName" />
            <button class="add" @click="add">添加任务</button>
        </header>
        <!-- 列表区域 -->
        <section class="main">
            <ul class="todo-list">
                <!-- 记得加  key 唯一标识 -->
                <li class="todo" v-for="(item,index) in list" :key="item.id">
                    <div class="view">
                        <span class="index">{{index +1}}</span> <label>{{item.todo}}</label>
                        <button class="destroy" @click="del(item.id)"></button>
                    </div>
                </li>
            </ul>
        </section>
        <!-- 统计和清空 -->
        <footer class="footer" v-show="list.length!==0">
            <!-- 统计 -->
            <span class="todo-count">合 计:<strong> {{list.length}}</strong></span>
            <!-- 清空 -->
            <button class="clear-completed" @click="clear">
                清空任务
            </button>
        </footer>
    </section>

    <!-- 底部 -->
    <script src="./vue.js"></script>
    <script>

        const app = new Vue({
            el: '#app',
            data: {
                list: [
                    { id: 1, todo: '唱跳' },
                    { id: 2, todo: 'rap' },
                    { id: 3, todo: '篮球' },
                    { id: 4, todo: 'dance' }
                ],
                todoName: ''
            },
            methods: {
                // 删除
                del(id) {
                    this.list = this.list.filter(item => item.id !== id)
                },
                // 添加
                add() {
                    if(this.todoName==''){
                        alert('输入待办事项')
                        return
                    }
                this.list.unshift({
                    id:+new Date(),
                    todo:this.todoName
                })
               this.todoName=``
                },
               clear(){
                this.list=[]
               }
            
            }
          
        })

    </script>
</body>

</html>